Flattening and removing device for a plastic tubular film web produced in a blowing process

ABSTRACT

A flattening and removing device for a plastic tubular film web produced by a stationary film blowing head in a blowing process has two deflecting rollers and two turning bars. The first deflecting roller and the squeezing roller are mounted parallel to each other between mounting plates that are rigidly connected to a turntable mounted in turning fashion in the frame floor. The second deflecting roller is connected by a support frame to a retainer having ends which are connected to gearwheels in eccentric fashion. The turning bars are each connected by support frames to gearwheels, and the center lines of all the gearwheels are aligned with each other and with an imaginary swivel axis. Thus, the diameter of the turning bars can be increased to the desired degree without impeding the passage of the flattened tubular film when the device is installed.

FIELD OF THE INVENTION

The invention relates to a flattening and removing device for a plastictubular film web produced in a blowing process by a stationary filmblowing head.

BACKGROUND OF THE INVENTION

In a device of this type, known from DE 20 35 584 A1, the flatteningplates are secured to an auxiliary frame which is mounted for turning toa primary frame by means of a transverse element and a supporting axle.Mounted laterally in the supporting axle and swivelable are a firstturning bar with its mounting and sleeve, the second deflecting rollerwith its mounting and sleeve, and a second turning bar with its mountingand sleeve. The deflecting rollers and turning bars are mounted in thesupporting axle in reversible, turning manner. Since the turning barsmust be positioned close to the vertical supporting axle and thedistance of the turning bar from the supporting axle can only bemodified within narrow limits, the diameter of the turning bars can alsoonly be modified within narrow limits; thus the diameter of the turningbars cannot be increased at will, which may nonetheless be desirable. Inthe known device, therefore, not only is the diameter of the turningbars restricted, the turning bars are also positioned very close to thevertical axle that supports them, and this makes it difficult to guidethe film webs around the turning bars when the device is installed.

SUMMARY OF THE INVENTION

The purpose of the invention therefore is to create a device of the typedescribed in which the diameter of the turning bars can be increased atwill, without impeding the passage of the flattened film tube when thedevice is installed.

This purpose is achieved in a device in which the first deflectingroller and the squeezing roller are accordingly mounted parallel to oneanother between mounting plates that are rigidly connected to aturntable mounted in turning fashion at the bottom of the frame. Thesecond deflecting roller is linked by a support frame to a retainerhaving ends that are eccentrically connected to gearwheels. The turningbars are also connected by support frames to gearwheels, and the centerlines of all gearwheels are aligned with each other and with animaginary swivel axis.

A device according to the invention permits the use of turning bars of adesired diameter, without the passage of the flattened film tube beingencumbered when the device is installed after the film blowing head isstarted up. A further advantage of the flattening and removing deviceaccording to the invention is that vibration and oscillation areavoided, inasmuch as the mounting plates for the squeezing rollers andthe flattening plates that lie adjacent to these mounting plates are nolonger suspended in freely vibrating fashion, but are rigidly connectedby struts to a turntable mounted in turning fashion in the frame floor.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention will be apparent fromthe embodiment depicted in the Figures:

FIG. 1 is a schematic side view of an embodiment of the flattening andremoving device according to the invention, in starting position (0°setting).

FIG. 2 is a detail of the embodiment of FIG. 1, shown in side view.

FIG. 3 is a simplified top view showing the position of the deflectingrollers and turning bars when the reversing device is in startingposition (0° setting).

FIG. 4 is a top view corresponding to FIG. 3 in which the deflectingrollers and turning bars are turned counterclockwise.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described with reference to FIGS. 1 to 4, in whichlike numerals represent like parts.

A tubular film 12 formed by an extruder with a film blowing head (notshown) is flattened by flattening plates 14, which are swivel-mounted inmounting plates 16. The mounting plates 16 are connected by connectingstruts 18 to a turntable 20, which is mounted for turning in the floor24 of a frame 22.

The turntable 20 includes a gear rim 26 which engages with a pinion thatis driven by a motor 30. The flattening plates 14 may be swung by meansof a servo-mechanism in the directions shown by the double-headed arrow"a"(FIG. 1), so as to vary the angle enclosed thereby.

The mounting plates 16 which are rigidly connected to the turntable 20also support squeezing rollers: 32 and a first deflecting roller 34positioned behind the squeezing rollers 32.

The tubular film 12 is flattened by the squeezing rollers 32 and ! sthen guided by the deflecting roller 34, as shown in FIG. 1. The ,tubular film is thereafter guided by a first turning bar 36, a seconddeflecting roller 38, and a second turning bar 40, before the flattenedtubular film is conducted out of the frame 22 and fed to an additionaltreatment device, such as a stationary winding apparatus or secondaryprocessing apparatus (not shown).

The squeezing rollers 32 and the first deflecting roller 34 are swungwhen the turntable 20 is made to turn by the motor-driven pinion 28. Themotor 30 drives a shaft 44 mounted in frame 22 by means of drive chain42. The turning motion is transmitted by a toothed belt 46 to a pulley48. The pulley 48 is secured in turning fashion to a support 50, whichis mounted to frame 22.

Positioned on the shaft of pulley 48 are two pinions 52 and 54, as shownin FIG. 2. The pinion 52 engages with a gearwheel 56, which is mountedin the support 50 by means of an axle 58. Connected in rigid fashion tothe free end of this axle 58 is a support frame 60 for the secondturning bar 40.

The pinion 54, which also is placed in turning motion by the pulley 48,engages with a gearwheel 62, which is mounted in turning fashion bymeans of a sleeve 64 in support 50. At the same time, the sleeve 64encloses the above-described axle 58 in such a way that the axis ofsymmetry of the gearwheel 56 is aligned with the axis of symmetry of thegearwheel 62. The axle 58 of the gearwheel 56 thus extends through thesleeve 64 and projects on the side at which it is connected to thesupport frame 60 for the second turning bar 40.

Eccentrically positioned on the gearwheel 62 that is put into turningmotion by the pinion 54 is a retainer 66, having a free end that iseccentrically connected in the same manner to a gearwheel 68. Thegearwheel 68 is the same size as the gearwheel 62 and its axis ofrotation is aligned in an imaginary line with the rotating axis of thegearwheel 62. Positioned on the retainer is a support frame 70 for thesecond deflecting roller 38, so that the support frame 70 for the seconddeflecting roller 38 can be horizontally swung by means of the gearwheel62 and the attached retainer.

The swinging motion is transmitted to the gearwheel 68 by the retainer.The gearwheel 68 is seated on a sleeve 74 that is mounted in turningfashion in a support 72 that is rigidly connected to the mounting plates16. Engaging with the gearwheel 68 is a pinion 76 that is mounted in thesupport 72 by means of an axle 78. The free end of the axle 78, whichprojects from the support 72 on the opposite side, bears a pinion 79that engages with a gearwheel 80. The gearwheel 80 is mounted in thesleeve 74, already described, by means of an axle 82 and runs throughthe support 72 and the center of the gearwheel 68. At its free end theaxle 82 is connected to a support frame 84 to which the first turningbar 36 is rigidly attached.

In FIG. 3 the already described reversing device is shown in zeroposition, i.e, the deflecting rollers 34 and 38 and the turning bars 36and 40 are not displaced relative to each other. The mounting plates 16are connected together by means of a corresponding connecting plate 90.At one rim of the frame 22, a deflecting roller 86 is shown by means ofwhich the tubular film web 12 is led out of the frame, as shown in FIG.1.

FIG. 4 shows the reversing device in a position in which the firstdeflecting roller 34 is rotated by 180° in counterclockwise direction.The turning bar 36 is swung 135° in counterclockwise direction. Thesecond deflecting roller 38 is swung 90° in counterclockwise directionand the second turning bar 40 is swung 45° in counterclockwisedirection. The same positioning is also possible in clockwise direction,so that 360° reversal is possible with the reversing device described.

In keeping with the embodiment shown here, the retainer 66 positionedbetween the gearwheels 62 and 68 may partially consist of a part 88which is rubber or another elastic material (cf. FIG. 3).

While the invention has been described above with respect to certainembodiments thereof, it will be appreciated by one skilled in the artthat variations and modifications may be made without departing from thespirit and scope of the invention.

What is claimed is:
 1. A flattening and removing device for a plastictubular film produced by a stationary film blowing head in a blowingprocess, said device comprising:flattening plates and squeezing rollerswhich are guided reversibly about an axis of a fed tubular film, astationary treatment device mounted downstream of said squeezingrollers, and first and second radially outward reversing deflectingrollers and first and second radially inward turning bars, over whichthe tubular film is led between the squeezing rollers and the treatmentdevice, wherein the deflecting rollers are each spaced from a respectiverotating axis thereof at a greater distance than a distance of theturning bars from a swivel axis thereof and each said deflecting rollersis able to swing to every possible swinging position along its rotatingaxis without being impeded; anda) the first deflecting roller (34) andthe squeezing rollers (32) are mounted parallel to each other betweenmounting plates (16), wherein the mounting plates are mounted rigidly toa turntable (20), said turntable being rotatably mounted in a framefloor (24), b) the second deflecting roller (38) is connected to aretainer (66) by way of a support frame (70), with ends of the retainer(66) being eccentrically connected to first and second gearwheels (62,68), c) the first and second turning bars (36, 40) are respectivelyconnected to third and fourth gearwheels (56, 80) by support frames (60,84), d) center lines of each of the gearwheels (56, 62, 68, 80) arealigned with each other and with an imaginary swivel axis of thedeflecting rollers (34, 38) and turning bars ( 36, 40), and e) the firstgearwheel (62) of the second deflecting roller (38) and the fourthgearwheel (56) of the second turning bar (40) are each driven by apinion (52, 54) arranged unrotatably on a shaft and the third gearwheel(80) of the first turning bar (36) meshes with a pinion (79) having arotary movement which is transmitted by means of a pinion (76) of thesecond gearwheel (68) of the second deflecting roller (38).
 2. A deviceaccording to claim 1, wherein the turntable mounted in turning fashionin the frame floor is set in turning motion by a motor-driven pinion. 3.A device according to claim 1, wherein the first gearwheel of the seconddeflecting roller and the fourth gearwheel of the second turning bar areeach driven by pinions positioned on a shaft, and third gearwheel of thefirst turning bar engages with a pinion having a turning motiontransmitted by a pinion of the second gearwheel of the second deflectingroller.
 4. A device according to claim 1, wherein all turning motion istransmitted by a motor.
 5. A device according to claim 1, wherein theflattening plates enclose an angle which is adjustable.